Many conventional digital and analog clocks utilize an electrochemical cell (commonly referred to as a “battery”) as a power source. A typical cell, such as an “AA” cell, delivers direct current at a potential of 1.5 volts. In such a clock, the electrochemical cell is the only power source. Modification of an existing conventional battery-operated clock for operation from a 120 volt AC line requires extensive modification and is impractical. Such a modification can also prevent later use of the clock as a battery-operated device, eliminating its portability, and preventing the clock from being used except when in proximity to a source of line current. Moreover, when the converted clock is operable only on line current, it will stop operating in the event of a power failure, and needs to be reset when power is restored.